This invention relates to a waveguide device, and more particularly to a waveguide holographic grating. Waveguide optics is currently being considered for a range of display and sensor applications for which the ability of waveguides to integrate multiple optical functions into a thin, transparent, lightweight substrate is of key importance. This new approach is stimulating new product developments including near-eye displays for Augmented Reality (AR) and Virtual Reality (VR), compact Heads Up Display (HUDs) for aviation and road transport and sensors for biometric and laser radar (LIDAR) applications. Waveguides are limited in terms of the range of ray angles that can be efficiently guided with a substrate. One solution addressed in the above references is to use holographic gratings for in-coupling and out-coupling light. However, while transmission holographic gratings perform these functions efficiently, their narrow angular bandwidth imposes even tighter angular limits on the image content that can be transmitted down a waveguide. Using the teachings contained in the above references it is possible to overcome these angular limitations by stacking or multiplexing gratings. Stacking is currently limited by holographic scatter while the number of gratings that can be multiplexed in a single waveguide is limited by current material modulation uniformity. One potentially very useful type of grating, called a fold grating, is unique in allowing changes in beam propagation direction and beam expansion to be accomplished in a single grating layer. However, prototype fold gratings have been found to have narrow angular bandwidths. There is therefore a need for a waveguide fold grating with an angular bandwidth that addresses the full angular capability of a waveguide.